The <canvas> element is not natively supported by the backend formatting engine. However, what can be done is to replace the <canvas> with an image in the print <div> before sending to the formatter. There are a few Javascript drawn <canvas> elements on this page. They are processed to the output by the xepOnine.jgPlugin.js Javascript by converting them on-the-fly to image format.
This is a second <canvas> element on the page:
Ad rebum est takimata. Diam molestie eos vero consectetuer facilisis. No ipsum nonumy vero sadipscing stet diam justo ipsum diam lorem ipsum dolor clita et stet nobis. Quis sanctus stet dolore sit nonummy ut duis lorem magna eirmod sed accusam sea in gubergren sanctus ipsum. Sadipscing sed sea ipsum sed elitr laoreet illum ipsum accumsan. Sea accusam sed dolor eos. Justo at invidunt quod nulla consetetur dolor et nulla dolores. Diam magna dolor et ea lorem.